Holograms viewable with nonlaser light sources have been produced with the image plane technique wherein the object is focused at or near the plane of the recording medium. Motion picture films have been holographed using this technique to produce moving stereoscopic images. In this technique, the film frames are imaged onto the hologram film to form narrow vertical strip holograms arranged in a contiguous manner. A plurality of the strip holograms provides a full view of the image in the horizontal plane. A full view of the image in the vertical plane is observed due to the chromatic dispersion properties of the hologram. These properties produce a rainbow colored image (rather than black and white or true color) which is viewable only over a limited range in the vertical direction.
The object of this invention is the production of a hologram of either a transparency or diffusely reflecting three dimensional object which has wide exit pupils in both the vertical and horizontal planes, can be viewed with a nonlaser illumination source, and is capable of reproducing the image in full color. Diffusers or directional dispersing elements are used in conjunction with anamorphic optics to achieve wide exit pupil angles. The techniques described in this application can be used to produce black and white or full color holograms of film transparencies or three dimensional objects which can be viewed with nonlaser light sources and display a wide viewing angle in the vertical direction. Similar techniques and concepts to extend viewing angles in holograms of different configurations are shown in U.S. Pat. Nos.: 3,625,584; 3,834,785 and 4,067,638. Holograms produced in accordance with this invention are uniquely different, however: these holograms provide a large aperture, wide angle view of the image which can be either in front or in back of the film, and no optical elements other than the hologram film and illumination source are required to view the image.